Gear mechanism



Feb. 27, 1940.

R. J. L. MOINEAU GEAR KECHANISM original-Filed April 18. 1935 :s shets-sneet 1 'fer'.rosepn Louis 1o-menu l Il `\\\\\\I\\\\\\\\\\\\\\\\\\\ 5 Sheets-Sheet 2 J'asepk Louls um." tau Ren e' INVENTOE.r

GEAR MECHANI SM- Original Filed April 18, 1935 Feb. 27, 1940.

Reoaued Feb. 27,1940

Re. 21,374 l UNI'I'ED` :STATI-:s PATENT ori-fici:

oaaanmonmsm Original No.2,085,115, dated June 29. 1937, Serial No. 16,959, April 18, 1935. 'Application for reiluo September 23, 1938, Serial No. 231,424.

In Moroooo May 2, 1984 (ci. 'zi-4st) lzclalms.

The present invention has for its object a gear mechanism adapted-for use as a pump. compresser, motor. or simple transmission device, and even. simultaneously. for several such uses. The saidmechanism is chiey characterized lby the tact that it comprises at least three helical gear elements mounted one within the other. In each group oi two meshing elements the eiement the threads of which are enveloped has one thread. or tooth. less than the enveloping elementandeachthreadortoothoftheenveloped element is also, in each transverse section, in constant contact with the enveloping element, the pitches. which may be constant or not, of the helices of these sets of'threads being in each cross-section. in the ratios represented by the ratios ot the numbers of teeth in the said elements.

Preferably, the said elements directly envelop one another, and each element has one thread or tooth more than the element which it directly envelope; each thread or tooth of one element is also, in each transverse section in constant contact with the adjacent element, the pitches, which may be constantyor not. of the helices or all of said elements being, in each cross-section,

in the ratios represented by the ratios oi the` numbers of teeth ot each ot the said elements.

By the combination ot at least three such elements, there may be obtained in the iirst place a greater output for a given size. a simpler construction.- a better balancing. as well as other features,y which will be set forth in the following description.

In the accompanying drawings. which are given solely by way of example:

Fig. 1 is a longitudinal section, on the line I-I of Fig. 2. of a simpledevice according to the invention;

Fig. 2 is a cross-section on Fla. 1:

Figs. 8 and 4 are geometric diagrams on a larger scale, showing diiIerent positions occupied by the three helical elements when the central element is rotated;

Fig. 5 represents the gear outlines;

Fig. 6 represents another set of outlines which are combined in another manner; 1

Fig. 'i represents, in longitudinal section. a

constniction of the mechanism shown in the une 2 2 0:

u wheels used :or grading;

'to the length` of the pitch, this being necessary l'or obtaining non-leaking conditions for the ele- Figs. 10 and 11 represent other modied embodiments of the mechanism according to the invention.

According to the embodiment represented in Figs. 1 and 2, the "mechanism comprises three 5 helical gear elements I, 2, l. located one within the other. The external element 3 comprises three teeth or threads, the intermediate element 2 comprises two such threads, andl the central element I `hasonly one tooth `or thread. The pitches o! the threads are constant, and are in the respective ratios of three-to-two and two-toone. The external helical element 3 is provided with threads the length of which is at least equal ments 2 3. The internal helical element I is mounted on a shaft 5 which is supported at its ends, in bearings 6; one of said bearingsmay be eliminated. The intermediate element 2 is quite free as to rotation and its thrust is limited at each end, iorinstance by discs 1-8 mounted on The external. element I is stationary. It is contained in the casing 9 or is formed in one with the casing, which is provided atl I0 and II with connections adapted for the admission or the discharge of the uid which either provides power or is transported by the mechanism.

The Ahelical elements I23 may consist of any suitable substance.

One or more of these elements may be made of elastic material (india rubber, for instance) in order to ensure better non-leaking conditions. and a better lubrication' in the case where for instance water is operated upon.

The intermediary element, for example. which may be very thin, may be constructed for instance by the stamping process, or by an electrolytic deposit upon a mould oi suitable form.

By an examination of Figs. 3 and 4, in which the helical elements are represented diagrammatically by their cross-sections takenat any point of their length, such sections being reduced to the corresponding basic curves. it will be at once observed that when rotating the section of the central element I about the point O' (representing the axis of this element), for instance in the direction of the arrow f' (Fig. 3), the center 02 of the cross-section of the intermediate element 2 will rotate about the center O' in the contrary direction (arrow f2) whereas this cross-section oi' the element 2 will rotate about its own center 0z in the same direction (arrow P). By comparing the Figures 3 and 4. it will ,be observed that when the element I proceeds, u

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The elements I and 2 may be given any suitable speed in the same direction or not; the outputs ci' the groups I, l and 2, I may be added or subtracted. It will be readily understood that suchamechanism canbeused,atwill.asapump, a compressor. a motor. or a simple power transmission device, and also, simultaneously for several of these uses. A

Fig. li represents a mechanism with i'our elements l-2-3-4, having the disposition shown diagrammatically in Fig. 6. It consists oi elements I and 3 having one and three concentric teeth, and of elements 2 and 4 having two and i'our concentric teeth. A driving pulley Il-Il- Il-Ili is mounted on each element. Il is a stationary bearing for the rotary `element I and l2 is a similar bearing for element 2.

The outputs oi.' this mechanism when used as apump, a compressor or a motor, are addedtogether. and the speeds of the pulleys have the ratios represented by the Figures 4, 3, 2, 1, and may be used in this manner as speed transmission devices. It is evident that the mechanisms of the types represented in Figs. 10 and 11, but

'of a more complicated nature, might comprise any number of helical elements having n, n+1, n+2 teeth.

All these groups oi' at least three helical elements, one within the other, have all the properties oi analogous mechanisms having two gearwheels, such as pumps, compressors, motors, or

simple transmission devices, and can even be emplpyed ior several of these uses at the same time.

A certain number of these mechanisms may also be grouped end-to-end, or in the parallel or the radial position, etc.

Obviously, the invention is not limited to the embodiments represented and described, which have been chosen only by way of example.

Having now described my invention, -what -I claim as new and desire to secure by Letters Patent is: 1

LA gear mechanism adapted to be employed rvas a pump, compressor, motor, transmission member and the like, or even simultaneously for a number oi such uses, comprising at least three helical gear elements. disposed the one within the others, each element having one helical thread more than the element immediately inside same, the threads of the enveloped elements being always in contact in each cross-section with the threads of the corresponding enveloping element and the ratio of the diil'erent pitches of these threads being equal to the ratio of the number of threads on said elements.

2. A gear mechanism according to claim 1, in which the pitch circles oi the elements oi' uneven number have a common center and the pitch circles oi' the elements of even number have also a common center diierent from the rst center.

3. Gear element according to claim l i'n which the intermediate element is made of thin sheet metal.

4. In apparatus of the class described, the combination of an inner rotor element which is externally threaded and mounted for rotation about a xed axis, an intermediate rotatable element having internal threads which cooperate with the threads on said inner element and which in number are one more than the number o! threads on said inner element, and an outer stationaryelement in which said intermedaite .element rotates about an axis odset from the axis of the threads o! the intermediate member.

5. In apparatus ofthe class described, the combination oi' an externally threaded inner rotor element, an internally threaded intermediate -rotatabie element the threads oi' which cooperate with the threaded exterior of said inner element and in number exceed the number of threads on said inner element by one, and an outer stationary element in which said intermediate element rotates, one oi said elements being srotatable about an axis oiset from the axis of the threads thereof.

6. *In apparatus of the class described, the combination of an externally threaded inner rotor element, an internally threaded intermediate rotatabie element the threads ci which cooperate with the threadedv exterior oi' said inner element and in number exceed the number of threads on said inner element by one, an outer stationary element in which said intermediate element rotates about an axis oiset from the axis of the threads oi the intermediate member, and a shaft connected with said inner element and-extending to the exterior of` said outer element, and means engaging the opposite ends of said intermediate element to prevent axial displacement thereof.

7. In apparatus of the class described, the combination of a casing, an inner rotor element which is externally threaded and mounted for rotation in bearings in said casing, an intermediate rotatable element having internal threads which cooperate with the threads on said inner element and which in number are one more than the number oi threads on said inner element, and a member fixed in said casing and in which said intermediate element rotates about an axis oii'set from the axis of the threads of the intermediate member.

8. In apparatus oi the class described,the combination of a casing, an inner rotor element which is externally threaded and mounted for `rotation in bearings in said casing, an intermodiate rotatable element having internal threads which cooperate with the threads on said inner element and which in number are one more than the number of threads on said inner element, said intermediate element also having external threads, and an element ilxed in said casing and having internal threads which cooperate with the external threads on said intermediate element and which in number are one more than the number ci' external threads on said intermediate elemen .f

9. In apparatus of the class described, the 'combination of a casing, an inner rotor element which is externally threaded and mounted for rotation in bearings in said casing, an intermediate rotatable element having internal threads which cooperate with the threads on said inner element and which in number are one more than the number of threads on said inner element, said intermediate element also having external threads the number of which is the same as the number of said internal threads, and an element thereof.

rotation in bearinss in said calins. an intermediate rotatable element having internal threads whichcoopexate withthethreadsonaaidinner element and which in number are one more than the number of threads on said inner element, said intermediate' element also having external threads, an element nxed in said casing and having internal threads which cooperate with the external threads on said intermediate element and m which in number are onemore than the number of external threads on said intermediate element, and means ensasins the ends of said intermediate element to vprevent axial .displacement 11. In apparatus of the classk described, the combination of a casing. an inner rotor element which is externally threaded and mounted for rotation in said casing, an intermediate rotatable element having internal threads which cooperate 20 with the threads on said inner element and which in number are 'one more than the number of threads on said inner element, an outer elementv ii'xcd in said casing and in which said intermediate eiementrotateaandintermeshingarson .saidinner and said intermediate elements.

12.mapparatusottheciassdeem'ibed,the combination of `a casing, an inner rotor element which is externally threaded and mounted for rotation in'bearinas in said casina, an intermediate rotatable element having internal threads -whichcooperatewlththethreadsonsaidinner element and which in number are one more than the number of threads on said inner element. said intermediate element also having external threads,aiixedelementinsaideasinghavinin ternal threads which cooperate with the external threads on said intermediate element and which in number are one more than the number of external threads on said intermediate element. a pair of intermeshinz gears on said inner and said intermediate elements, and a pair of intermeshing gears one of which is on said intermediate and the other of which is in nxed relation to said fixed element.

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